Osama bin Laden's alleged bodyguard and chauffeur today becomes Guantanamo Bay's first terror suspect brought before a US military commission that allows for secret evidence and no government appeals.

Salim Ahmed Hamdan, a 34-year-old Yemeni, has said he earned a pittance for his family by driving al-Qaida's leader before the September 11 attacks, but denies supporting terrorism.

"This process goes against everything that we fought for in the history of the United States," said Lt Cmdr Charlie Swift, Hamdan's lawyer.

Representatives from Amnesty International, the American Civil Liberties Union, Human Rights Watch, Human Rights First and the American Bar Association were offered seats as observers for the pre-trial hearings, but military officials have refused to let them tour the Cuban prison.

Hamdan and three others appearing face life in prison, though some defendants could face the death penalty.